docs: def get_port_vendor_info(port=None):
      """ Return vendor informations of a usb2serial device.
          It may depends on the Operating System.
          :param string port: port of the usb2serial device
  
          :Example:
  
          Result with a USB2Dynamixel on Linux:
          In [1]: import pypot.dynamixel
          In [2]: pypot.dynamixel.get_port_vendor_info('/dev/ttyUSB0')
          Out[2]: 'USB VID:PID=0403:6001 SNR=A7005LKE' """
  
      port_info_dict = dict((x[0], x[2]) for x in serial.tools.list_ports.comports())
      return port_info_dict[port] if port is not None else port_info_dict